Participants were assessed using standard clinical psychiatric interviews. The screening programme used instruments to detect anxiety, depression, their degree of perceived disability and body image.

It also assessed their quality of life, multidimensional body-self relations and appearance scales.

Out of the 105 participants, 70 per cent of whom were women, 24 per cent showed signs of anxiety and 13 per cent were found to have depression.

Dr Ayman Soliman, who performed the surgery on Mr Al Suwaidi, said depression was a common condition in patients who wanted bariatric surgery.

“In Marwan’s case, we know he was suffering depression as he could not leave his home,” he said.

“He was barely able to stand up, and could not go to the bathroom independently.

“There was also cellulitis, lymphedema and swollen legs.

“Not only will he experience weight reduction but he will regain his confidence and have a better outlook on life, with an opportunity to work, establish relationships and hopefully get married. Hopefully this will also improve his mental state.”

The Al Ain study also found that participants perceived themselves to have functional disabilities at work or school (27 per cent), social life (36 per cent), family or at home (35 per cent), and in religious duties (39 per cent). And those who believed their abilities were impaired by their weight were more likely to suffer anxiety or depression.

Obesity is a rapidly growing global problem of epidemic proportions and is especially prevalent in economically developed countries such as the UAE.

According to the Global Burden of Disease Study 2013, more than 66 per cent of men and 60 per cent of women in the UAE are overweight or obese.

While a healthy body mass index is suggested by doctors to range between 18 and 25, a BMI over 40 is considered a potential candidate for bariatric surgery.

Obese people are increasingly considering bariatric surgery as an easy means to reduce excess body fat.

Researchers concluded that there was a greater need for more engagement from primary care providers in the mental health screening of patients. They also said there should be more early intervention by doctors and referrals of obese patients, especially those patients seeking or pursuing bariatric surgery, to specialist facilities.